The present disclosure relates generally to information systems, and more particularly to actively modulated plasmonic components.
Information can be transferred electrically through copper wires, or optically through optical fibers and waveguides. Of equal importance as efficient data transmission is the manipulation of the information-carrying signal, in order to transmit, route or receive information. Here, the methods differ strongly between electrical and optical domains mainly because of their underlying physical mechanisms. Whereas active electronic building blocks, e.g. transistors, are nowadays well below 100 nm in size, the optical counterparts are several 100 μm up to mm's in size, fundamentally limited by the diffraction limit and electro-optical manipulation efficiencies. These boundary conditions constitute a large size discrepancy being present between the electronic and optical building blocks. This offsets the greater bandwidth and speed advantages of photonic concepts and limits the attractiveness of a co-integration of optical and electronic components on the same platform with similar integration densities.
Collective oscillations of electrons in a medium with free or mobile charge carriers, e.g. a metal or a highly-doped semiconductor, coupled to an optical wave at the interface of the metal and a dielectric are called Surface Plasmon Polaritons (SPP). SPPs enable light to be confined to volumes of a few tens of nm3 which enables light to be manipulated below the diffraction limit with very high efficiencies and further also guided along the dielectric-conductor interface at optical subwavelength dimensions and at optical frequencies. On the one hand, plasmon-based devices thus offer the potential of integrating optical components with dimensions much closer to state-of-the-art semiconductor electronic devices compared to today's photonic building blocks. This would enable not only increased bandwidth for short and long-range communication, electro-optical or all-optical switching etc., but furthermore a significant reduction in cost and total complexity due to the monolithic integration of electronic and optical components on a common platform. Therefore, it is desirable to create micrometer-sized low-loss plasmonic modulators, switches, routers and mixers for co-integration of electronics and optics at nanometer dimensions below the diffraction limit, based on manipulation of plasmon propagations by controlling the free charge carrier concentration in a nano-metal sized semiconductor segment seamlessly embedded into the SPP-carrying waveguide and being electrically controlled causing a conductor-to-insulator transition in the semiconductor segment.
Therefore, heretofore unaddressed needs still exist in the art to address the aforementioned deficiencies and inadequacies.